An exemplary embodiment according to the present invention relates to a memory element for a device for monitoring the functioning of a system. A computer program for execution on a computer, for example, on a microprocessor, is stored on the memory element. The memory element may be designed, for example, as a read-only memory, a random access memory or a flash memory.
In addition, an exemplary embodiment according to the present invention relates to a computer program for execution on a computer, for example, a microprocessor.
An exemplary device according to the present invention monitors the functioning of a system having lower-level subsystems or a device that is a component of a higher-level system. This system may have hardware components, including sensors, actuators and/or function computers. The device may also check input signals, output signals and functions of the system.
An exemplary automotive control device according to the present invention controls and/or regulates one or more functions in a motor vehicle. The functioning of the control device may be checked on the basis of input signals (from sensors or other control devices), output signals (for actuators or other control devices) and the functions of the control device. The control device may have subordinate subsystems, e.g., additional control devices for controlling and/or regulating the individual subfunctions of the vehicle. An example of a system having subordinate subsystems is an electric brake system of a vehicle. A higher-level control device determines how a preselectable braking force is distributed among the individual brake cylinders of the wheels. Subordinate control devices assigned to the brake cylinders of a wheel, for example, may control or regulate the driving of the brake cylinders.
To guarantee, or at least make more probable, the correct functioning of a system, the monitoring of input signals, output signals and functions of the system may be relied upon. German Published Patent Application No. 41 14 999 refers to a method of monitoring the functioning of an automotive control device. The intended function of the control device is executed in a microprocessor of the control device. In parallel, the same function is executed at least partially in a monitoring device. The output signals of the microcomputer and the monitoring device are compared and, depending on the result of this comparison, a determination is made as to whether the control device is functioning correctly. If faulty functioning of the control device is detected, appropriate substitute measures may be instituted. It is believed that this method is based on the hardware of the system to be monitored and is highly inflexible. If the proposed monitoring method is to be executed, for example, in another control device having another intended function, it is believed that the monitoring method will have to be completely revised and be adapted to the revised function of the other control device. German Published Patent Application No. 44 38 714 refers to a method of monitoring the functioning of a control device. A microcomputer of the control device is subdivided into a function level, a monitoring level, and a check level. The function of the control device is executed in the function level. In the monitoring level, the function executed may be checked, for example, by a threshold comparison or a plausibility check. In the monitoring level, the total function of the control device is therefore not executed, and instead only specific monitoring functions are executed. Nevertheless, to detect faulty functioning of the system with adequate reliability, the additional check level checks the hardware components of the system (e.g. memory elements), and may check correct functioning of the microprocessor using a question-answer communication. It is believed that this monitoring method has the disadvantage in that its structure is based on the hardware of the system to be monitored and is very inflexible. To apply the monitoring method to a different control device having a different intended function, it is believed that this monitoring method will first have to be completely revised and adapted to the new hardware and software conditions. However, this may be complicated and expensive.